The operation of conventional plasma arc torches is well known and understood by those having ordinary skill in the art. The basic components of these torches are a body, an electrode, mounted in the body, a nozzle defining an orifice for a plasma arc, a source of an ionizable gas, and an electrical supply for producing an arc in the gas.
Initiation of a torch start up sequence involves supplying an electrical current to the electrode, typically a cathode, and the pilot arc is initiated in a pre-flow supply of ionizable gas between the electrode and the nozzle. A flow of a plasma gas is then directed from the electrode to the work piece, wherein the work piece defines the anode and a plasma arc is generated from the electrode to the work piece. Suitable ionizable gases include non-reactive gases such as nitrogen, or reactive gases such as oxygen or air. Shield gases are also employed to increase the efficiency and efficacy of the torch cutting process.
The control and regulation of the various supply gases (preflow, plasma and shield) is needed in order to obtain a high quality, economical cut. Improper supply gas pressures may damage or shorten the shorten the operating life of the torch nozzle and electrode components.
Torch operators frequently rely upon cutting charts to help determine proper combinations of gas and pressure with respect to the work piece material, thickness of the workpiece, operating currents, and desired plasma gas and gas pressures. Frequently, an operator may change an operating parameter without full realization of how the adjustment may impact other attributes of the torch performance. Frequently, operator adjustments lead to less than optimal performance which in turn increases operating costs and contribute to a shortened torch component life.